As one of the technological problems in the conventional PDP device, luminous efficacy [lm/W] has to be improved for the reduction of power consumption and the increase of luminance. One example of a method for improving the luminous efficacy is described in Japanese Patent No. 3242096 (Patent Document 1). In this method, in the sustain discharge in a sustain operation of the drive control in a subfield, the peak of the discharge emission is separated into to peaks, thereby achieving the improvement of luminous efficacy.
As an example of the conventional sustain operation, a driving waveform for the basic sustain discharge (referred to as first-type waveform (A)) is shown in FIG. 6. In this operation, for a single driving waveform (Px/Py), the discharge emission (E) forms one peak, that is, almost one discharge peak (511) is formed (timing t4). The applied voltage value of the driving waveform (Px/Py) ranges from −Vs (negative sustain voltage) to Vs (positive sustain voltage).
As another example of the conventional sustain operation other than the waveform (A), a driving waveform for the sustain discharge in which the peak of the discharge emission is separated into two peaks (referred to as second-type waveform (B)) as described in the Patent Document 1 is shown in FIG. 7. In this operation, for a single driving waveform (Px/Py), the discharge emission (E) forms two separate discharge peaks (521 and 522) (timing t11 and t14).